Audio glitches when exporting master file

When exporting the master file with sound there are areas where audio pieces get looped.. when i refer back to the project there is not even an audio file there.. . even when i export just a WAV of the audio the issue is still there.. In an hour and 45 minute feature this happens 4-5 times.. this is unacceptable and very frustrating..

I am on the original Premiere Pro 2015CC version, little nervous about updating in the middle of the project.. i tried cutting out the looped audio from the wav export and re-exporting in the newest version Premiere and it worked fine..

my idea is to have it done right first time and not to have to export it twice, once for sound once for picture.. at this stage its not a master but needs to be watched by producers without glitches in the audio.. my export setting is vimeo720p in media encoder..

You didn't mention anything about mp3 audio, which is my point. It can cause problems. Problems such as the ones you face. So I repeat: if there is mp3 audio in your project, you do yourself no favors by keeping it there. Replace it.